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  1. #1
    Join Date
    Feb 2005
    For the past couple of days my furnace
    (Rheem classic 90 plus) is making a vibrating noise.

    I checked the blower motor and saw if there was any play
    in it.

    There is no play sideways but when I tried to pull the
    motor shaft there was a slight play (moved a bit)

    Does this mean the motor bearings are starting to wear out?

    My furnace is about 7 years old. Is this a timeframe when
    the motor starts developing problems?

    Also the fan blades look OK to me. There was some light
    dust stuck to the blades but they seem OK.

    I am pretty sure the noise I heard was coming from the motor.

    Assuming the motor has to be replaced to get rid of the
    noise, there is a capacitor which needs to be disconnected
    to access the squirrel cage. How do I discharge the

    Is it enough if I touch a multimeter to the capacitor
    terminals? I don't want to get a schock from the capacitor.

    Also is replacing the blower motor easy? (1-2 Hr job)
    Since is is pretty cold here and I don't want to have
    the furnace down a long time.

    Thanks a lot for your help.


  2. #2
    Join Date
    Feb 2004
    chicago suburbs
    no someone before you hurt yourself. you're already scaring me.

  3. #3
    Modman Guest
    New motors have the movement you're talking about (thrust). Yours may be excessive but before I'd replace I'd remove and clean the wheel. Warning though, sometimes there tough to get apart and may require a puller that a tech will have on him that a do it yourselfer won't. A tech can also evaluate the thrust and tell you if it's excessive. Good luck!

  4. #4
    Join Date
    Feb 2005
    Hi Modman,
    Thank you,

    Can a dirty blower wheel cause the vibration I described?
    I have not cleaned the blower wheel the past 7 years.

    But I don't understand why the vibration would start
    suddenly from the past couple of days?

    If something gets stuck in the blower wheel will that
    cause an imbalance in the wheel and cause the vibration?



  5. #5
    Modman Guest
    Yes to all

  6. #6
    Join Date
    Feb 2005

    Vibration still there after cleaning

    As recommended I cleaned by blower wheel. There
    was dirt stuck over the fins which I cleaned after removing
    the wheel.

    But the vibrartion from the motor is still there.

    I checked the motor and found it OK. The wheel spins smoothly.
    and there is no play sideways, only a little in and out. There is no queaking sound which would indicate a bearing problem.

    Why would the vibration suddenly start for the past four

    Does the wheel need replacement after some interval? As I
    had said earlier my furnace is 7 years old.

    Is the whell like a car tire which needs balancing at regular intervals?

    Will the vibrartion go away if I change the wheel?



  7. #7
    On the wheel there may have been some balancing weights that came off. This would be a spontaneous event and would cause the wheel to vibrate in a harmonic type of noise. In this case you would probably be better off to get a new wheel. If the motor is ok now it will soon fail if the wheel is the problem.

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